Can you post a picture of what you mean? Without knowing what hardware you're talking about, what kind of purse it's on and when it was made, it's impossible to give an answer.
In fact, there's NO "One Rule Fits All" about that kind of thing. Details on Coaches changed constantly and you can never compare the details on one style of purse with another style or plant or year. If you're using what you asked about to authenticate something, please ssk here instead and let us take a look.
If you mean the underside of the oval turnlock, then yes, having indentations where the folded-over prongs fit into instead of a smooth surface is a red flag especially when the prongs are much shorter than the indentations, but turnlock hardware may have been replaced with a non-Coach turnlock, and just on its own IMO isn't proof enough that something's fake, it just means that an expert needs to take a good look at the entire purse. But if you're thinking of buying a Coach purse and it has that kind of turnlock back, hit the Back button or put it back on the shelf if you don't have a chance to ask about it here before buying it.
Nothing that's easily replaceable, like straps, turnlocks, and especially hangtags, should ever be used as the ONLY proof that something's fake. Even more important is a clear photo of the creed stamp and serial number and the area around it.
Is the picture below what you're asking about?
it is off and one where I live!:/
How to be more sure about it? E.g. more clearer pics?
